Distal 22q11.2 microduplication combined with typical 22q11.2 proximal deletion: A case report.

[22q11.2 deletion syndrome]

The 22 q 11 chromosomal region contains low copy repeats (LCRs ) sequences that mediate non-allelic homologous recombination , which predisposes to copy number variations (CNVs ) at this locus . Hemizygous deletions of the proximal 22 q 11 .2 region result in the 22 q 11 .2 deletion syndrome (22 q 11 .2 DS ). In addition , 22 q 11 .2 duplications involving the distal LCR 22 s have been reported . This article describes a patient presenting a 2 .5 -Mb de novo deletion at proximal 22 q 11 .21 region (between LCRs A-D ), combined with a 1 .3 -Mb maternally inherited duplication at distal 22 q 11 .23 region (between LCRs F-H ). The presence of concomitant chromosomal imbalances found in this patient has not been reported previously . Clinical and molecular data were compared with literature , in order to contribute to genotype-phenotype correlation . These findings exemplify the complexity and genetic heterogeneity observed in 22 q 11 .2 deletion syndrome and highlights the difficulty to make genetic counseling and predict phenotypic consequences in these situations . © 2014 Wiley Periodicals , Inc .